Variable configuration bending neck for an articulating ultrasound probe

ABSTRACT

A bending neck for an articulating ultrasound probe has a variable configuration whereby different sections of the bending neck can be bent into different curvatures. In one implementation a rigid member is extended into the bending neck, setting the deflection point for a section of the bending neck at the end of the rigid member. In another implementation the links of the bending neck have different lengths, causing different sections to have different radii of maximum curvature. In another implementation the bending neck is encased in a sheath which exhibits regions of different durometer, thickness, or spacing of points of attachment to the bending neck.

This application is the U.S. National Phase application under 35 U.S.C.§ 371 of International Application No. PCT/IB2016/051166, filed on Mar.2, 2016, which claims the benefit of Provisional Application Ser. No.62/126,750, filed Mar. 2, 2015. These applications are herebyincorporated by reference herein.

This invention relates to ultrasonic imaging probes and, in particular,to bending necks for articulating ultrasound probes.

Some ultrasound probes are designed for imaging from within the body,including catheter probes and transesophageal echocardiography (TEE)probes. In these probes the imaging transducer is located at the tip ofthe probe, which is generally designed to be articulated by the operatorso as to obtain the desired view. The preferred way to articulate theprobe tip, particularly in the case of TEE probes, is by means of adistal section of the catheter or gastroscope referred to as a bendingneck. The bending neck is formed by a series of links which arepivotally connected to each other. This enables each link to moveslightly with respect to its adjoining links and hence the entiresection of links can be made to controllably articulate over asubstantial angle of bending. Control of the articulation is done bycables extending through the probe and the bending neck which arewrapped about the shaft or pulley of a control knob or motor in thecontrol unit at the proximal end of the probe. As the operator turns aknob or actuates a motor, a desired cable is pulled, which bends thearticulating neck section of the probe. Generally the pivot axis betweenlinks alternates by 90° from link to link so that some axes can bend inthe 0° 480° directions while the others can bend in the 90°-270°directions. The use of two controls and control cables for these twoaxis directions enables the operator to articulate the bending neck inany of these directions or any direction in between. The links and hencethe bending neck is hollow, enabling the wiring for the transducer atthe distal tip as well as other items such as guide wires and surgicaltools to pass through the probe for operation at or through the tip ofthe probe.

The fabrication and assembly of a bending neck for an articulating probecan be painstaking and costly. Each link of the neck must beindividually formed, then the links are joined by pins or rivets so thatthey will pivot with respect to each other. It is desirable to have aneasier and less costly way to build a bending neck, yet still have thewide range of articulation and articulation control which users demand.

In accordance with the principles of the present invention, a bendingneck for a controllably articulating ultrasound probe is provided whichis formed from a single tube or nested tube set. The tube is etched ormachined to form individual, pivoting links. A groove formed in one ofthe tubes of the nested tube set, or indentations in a single tubeprovide the control cable passageway. The bending neck curvature isformed to be variable, as by the use of movable bending points, multiplecontrol cable anchor points, varying pivot axis spacing, andmulti-durometer neck sheaths.

In the drawings:

FIGS. 1 and 1A illustrate a section of a bending neck formed from asingle nested set of two tubes.

FIGS. 2 and 2A illustrate a section of a bending neck formed from asingle tube, including an integral control cable passageway.

FIG. 3 illustrates a bending neck of the present invention with avariable bending deflection point.

FIG. 4 illustrates a bending neck with varied link spacing to providevariable articulation.

FIG. 5 is a detailed view of a technique for determining thelink-to-link articulation angle for a bending neck of the presentinvention.

FIG. 6 illustrates a variable durometer sheath which provides variablebending for a bending neck of the present invention.

FIGS. 7 and 8 illustrate the use of multiple control cable anchor pointsto controllably vary the bending of a bending neck of the presentinvention.

FIG. 9 illustrates a bending neck which can be controllably bent in twodifferent planes through the use of differently anchored control cables.

FIGS. 10a and 10b illustrate a variably articulating bending neck whichis controllable articulated by two bending sections in one plane.

FIGS. 11a and 11b illustrate a variably articulating bending neck whichis controllable articulated by two bending sections in two planes.

Referring first to FIG. 1, a single piece bending neck 10 for anarticulating ultrasound probe is shown which is formed of two concentrictubes, generally made of a metal such as stainless steel. The inner tube10 b fits tightly within the outer tube 10 a. Before insertion, twolongitudinal grooves 12 are formed on opposite sides along the length ofthe outside of tube 10 b. These grooves form passageways for controlcables that control the articulation of the bending neck as describedbelow. The grooves 12 are clearly shown in the cross-sectional view ofFIG. 1A. With the two tubes concentrically positioned, they are then cutinto separate links 11 by laser cutting toward the longitudinal axis ofthe tube or by another machining technique. The links are formed so asto remain movably connected to each other, as by lobes 14 extending fromone link to the next and located on opposite sides of the links. Theselobes and the spacing between the links formed by the machining processenable the adjacent links to move and pivot with respect to each otherabout axes extending through opposing lobes on opposite sides of thelinks. While each link may only pivot a small angle with respect to itsneighbor, a number of successive links forming a bending neck maytogether bend in a considerable curve. This is the desired articulation,significant enough to be able to position the distal end of the probewhere needed, but not sharp enough at any articular point so as to bindthe wires, tools, and other items passing through the central lumen ofthe bending neck.

FIG. 2 illustrates a second implementation of a single piece bendingneck, this time using just a single tube 10. The tube 10 is machinedinto separate connected links as described above, the grooves 15 betweenseparate links being shown in this drawing. Since the inner tube usedfor the control cable groove is not present in this single tubeimplementation, a series of ring-like indentations 16 are formed onopposite sides of the tube to convey the control cables through thebending neck. Two parallel cuts are made through the tube wall, then thearea between the cuts is pressed inward, forming the indentations asclearly shown in the cross-sectional view of FIG. 2A. The indentationsare formed on the tube sides which are 90° around the tube from thelines of pivot lobes 14, which are on the top and bottom and cannot beseen in the view of FIG. 2. As the control cables passing though theindentations on opposite sides of the tube are pulled after beinganchored at the distal end of the bending neck. They will respectivelycause the neck to bend into and out of the plane of the drawing of FIG.2.

There are a number of ways that the bending of a bending neck of thepresent invention can be controlled and adjusted. One control techniqueis to control the deflection point from which the bending takes place.FIG. 3 illustrates a technique in which a rigid member 18 is located inthe bending neck with its distal end at the desired deflection point. Inthis case the rigid member is a tube 18 and this partially cut-away viewshows links to the left of the tube 18 which are free to pivot abouttheir pivot lobes, while the links through which the tube is located areimmobilized from pivoting. The position of the deflection point isadjustable by adjusting the extension of the rigid member 18 into andout of the bending neck.

The angle subtended by the curvature of a section of the bending neckcan be set by selectively determining the lengths of individual links asillustrated by the bending neck 10 of FIG. 4. In this implementation thelinks to the left with pivot lobes 14 are relatively short and thelength of these links can bend with a relatively shorter radius ofcurvature. The larger links to the right with the pivot lobes 24 willbend maximally with a relatively larger radius of curvature. Inaddition, the different size links have different moments, whichdetermine which set of links will bend first when commonly controlled.The smaller links with the pivot lobes 14, having smaller moments, willbend first. This is useful, for instance, when the placement of atransducer at the distal tip of the smaller links (left side of thedrawing) is being controlled. The articulation of both sections of thebending neck is set to approximately the desired position by pullingrelatively forcefully on the control cables in the grooves 12 andthereby causing both sections to bend. With the transducer near itsdesired position, light pulling of the cables is used to move only thedistal section of smaller links to finely adjust the final desiredposition of the transducer.

The degree of pivoting between adjacent links is a function of thegroove that is machined through the tube to form separate links. FIG. 5is a partial side view of a portion of a bending neck where separatelinks 11 have been formed by machining groove 15 through the tube. Thetwo links can pivot around pivot lobe 14 by the width of the groove 15,opening and closing the groove 90° on either side of the axis of thepivot lobes. If greater pivoting is desired the groove can be machinedwith a tapered width with a maximum opening of theta above and below thepivot lobes. The relative pivoting of the adjacent links is therebyincreased to the dimension of angle theta.

Another technique for providing variable bending of a bending neck is toenclose the bending neck in a sheath with a variable durometer. FIG. 6illustrates a sheath 20 over a bending neck with a variable durometerfrom the distal end to the left to the proximal end of the bending neck.The sheath is relatively stiffer (higher durometer) to the right, whichbecomes less stiff toward the distal end of the sheath. When the controlcables are actuated to bend the bending neck, the distal end will bendfirst and more easily than the higher durometer proximal section of thebending neck. The durometer can be set by the choice of materials usedalong the length of the sheath. Another way to achieve the same resultis to vary the thickness of the sheath material along the length of thesheath. The dashed lines 22 in FIG. 6 indicate that the sheath 20 isthicker toward its proximal (right) end than it is toward and at thedistal end. Yet another way to achieve the same result is through theway in which the sheath is affixed to the bending neck. In the exampleof FIG. 6 the sheath 20 is tacked to the bending neck at closely spacedpoints 26 along the proximal portion of the bending neck, and is tackedto the bending neck at more widely spaced points 28 along the distalportion of the bending neck. This will cause the distal portion of thebending neck to bend more easily and readily than the proximal portion.

In some implementations it may be desirable to controllably bend asection of a bending neck at some times, and lock it in an unbentconfiguration at others. FIG. 7 illustrates an implementation of thisfeature using the embodiment of FIG. 4. In this case there are two setsof control cables, 40-42′ and 42-42′, extending through the controlcable passageways 12. The ends of cables 40-40′ are anchored byattachment to the distal link (leftmost) of the bending neck 10 as shownby anchor points 32 and 34 in FIG. 8. In FIG. 8 the inner tube 10 b hasbeen removed for clarity of illustration. The ends of the other set42-42′ of cables are anchored to link 11′, the first link followingthose with pivot lobes 24, as shown by anchor points 36 and 38. Wheneach pair of cables is pulled and relaxed in complementary fashion, thecorresponding section of the bending neck is bent in the plane of thedrawing, cable set 40-40′ controlling the distal (small link) sectionand cable set 42-42′ controlling the proximal (larger link) section. Butwhen both of cables 42-42′ are pulled in unison, the links of theproximal section are pulled together and locked into a straightconfiguration as shown in FIG. 7. The distal section of the bending neckcan still be controllably articulated by use of cables 40-40′. Whencables 40 and 40′ are pulled in unison, the entire bending neck islocked in a straight configuration. Thus, by using multiple controlcables and selected anchor points, different sections of a bending neckcan be locked or articulated.

In the implementation of FIG. 7 the pivot lobes are all on the front andback of the bending neck, which allows both articulating sections to becurved in the same plane, the plane of the drawing. A single set ofcontrol cable passageways 12 accommodates both sets of cables for thisarticulation. FIG. 9 illustrates an implementation in which pivot lobes14 are formed in the front and back sides of the tube and hence theirpivot axes are all normal to the plane of the drawing. The pivot lobes24 of the proximal section of the bending neck, however, are formed onthe top and bottom of the tube and have their pivot axes parallel to theplane of the drawing. This means that the distal section with pivotlobes 14 can be curved in the plane of the drawing whereas the proximalsection of links can be curved orthogonally into and out of the drawingplane. To control these different actions different sets of controlcables are used. Cables 42 and 42′ extend through cable passageways 12and are anchored at the ends at anchor points 32 and 34. These cablescontrol the articulation of the distal (leftmost) section of the bendingneck. The control cables 40 and 40′ for the proximal section of thebending neck are oriented 90° around the circumference of the tube fromcables 42 and 42′. These control cables must pass through their own,differently positioned control cable passageways oriented 90° relativeto passageways 12. These control cables 40 and 40′ are anchored at thedistal end of the section of links they control as shown by cable 40anchored at anchor point 36 in the cutaway view of FIG. 9. (Cable 40′and its anchor point are cut away in this view.) When cables 42-42′ arepulled the distal section of links is articulated or locked, and whencables 40-40′ are pulled the proximal section of links is controlled.

FIGS. 10a-10b are perspective views of an articulating ultrasound probeof the present invention. This probe has two straight, non-articulatingsections 60 and 62 and two articulating sections 70 and 72. Like theimplementation of FIG. 7, the articulating sections 70 and 72 articulatein the same plane, the horizontal plane H of the drawings. In FIG. 10athe short articulating section 70 is curved by control of its cablesanchored at the distal end of section 70. In FIG. 10b the cable setanchored at the distal end of section 72 has been used to articulatesection 72. Since all articulation is in the same plane, the pivot lobesof both sections are on the same sides of the section, and only a singlepair of cable passageways is necessary for the control cables of bothsections.

FIGS. 11a-11b are perspective views of another articulating ultrasoundprobe of the present invention, this one implementing articulation intwo planes as in the case of FIG. 9. Like FIG. 9, the articulatingsection 72 of FIG. 11a has its pivot lobes, pivot axes, and controlcable passageways oriented 90° around the circumference of the tube ascompared with those of articulating section 70. As FIGS. 11a and 11billustrate, the distal section 72 can be controllably articulated up anddown in the vertical (V) direction.

Other variations of the above concepts will readily occur to thoseskilled in the art. The pivot lobes may be formed in other shapes andsizes, and pivoting between links can be provided by other, morecomplicated pin or rivet configurations. However, the implementationsillustrated herein have the advantage of being wholly formed from asingle or concentric pair of tubes. Instead of sections of identicallyoriented links, an articulating section can be interspersed with linkspivoting at 90° with respect to each other, giving an articulatingsection the ability to be curved in almost any direction.

What is claimed is:
 1. An articulating bending neck for an ultrasoundprobe comprising: a plurality of pivotally connected links comprising alink and an adjoining link, wherein each of the plurality of pivotallyconnected links comprises an outer tubular segment and an inner tubularsegment fitting within and in contact with the outer tubular segmentaround an outer perimeter of the inner tubular segment, wherein the linkand the adjoining link are completely separated by a groove and remainconnected to one another by a pivot lobe of the link and a shape of theadjoining link receiving the pivot lobe, wherein, in an articulationconfiguration: a width of the groove is positioned between an entire endof the link and an entire opposite end of the adjoining link; and thelink and the adjoining link are configured to pivot relative to oneanother around the pivot lobe by the width of the groove, wherein, in alocked configuration: the link and the adjoining link are pulledtogether; and the entire end of the link is immediately adjacent to theentire opposite end of the adjoining link such that the link and theadjoining link are prevented from pivoting relative to another, whereinthe pivot lobe comprises an outer pivot lobe portion from the outertubular segment and an inner pivot lobe portion from the inner tubularsegment, wherein the groove extends through the outer tubular segmentand the inner tubular segment such that: the groove defines the pivotlobe and the shape of the adjoining link receiving the pivot lobe; andthe outer pivot lobe portion and the inner pivot lobe portion arealigned with one another, and wherein, in the articulationconfiguration, the link and the adjoining link are configured to pivotrelative to one another without a pin or rivet joining the link and theadjoining link.
 2. The articulating bending neck of claim 1, furthercomprising: a rigid member extending into a section of the articulatingbending neck, wherein a deflection point for curvature of the section ofthe articulating bending neck is determined by a position of the rigidmember.
 3. The articulating bending neck of claim 2, wherein the rigidmember further comprises a tube extending into the section of thearticulating bending neck, wherein the section of the articulatingbending neck comprises a subset of the plurality of pivotally connectedlinks that are rendered inarticulable to form a straight section.
 4. Thearticulating bending neck of claim 1, further comprising: a plurality ofpivot axes extending through the plurality of pivotally connected linksand about which the plurality of pivotally connected links pivot,wherein a first section of the articulating bending neck has relativelyclosely spaced pivot axes and a second section of the articulatingbending neck has relatively more widely spaced pivot axes.
 5. Thearticulating bending neck of claim 4, wherein the first section has arelatively smaller radius of maximum curvature and the second sectionhas a relatively larger radius of maximum curvature.
 6. The articulatingbending neck of claim 4, wherein the first section comprises a firstsubset of the plurality of pivotally connected links and the secondsection comprises a second subset of the plurality of pivotallyconnected links, wherein the first subset of the plurality of pivotallyconnected links exhibit a smaller moment than the second subset of theplurality of pivotally connected links.
 7. The articulating bending neckof claim 4, wherein the link and the adjoining link remain connected toone another by a further pivot lobe of the link and a further shape ofthe adjoining link receiving the further pivot lobe, wherein the pivotlobe and the further pivot lobe are opposite to one another around acircumference of the articulating bending neck such that the pivot axisextends through the pivot lobe and the further pivot lobe, and whereinthe shape of the adjoining link and the further shape of the adjoininglink are opposite to one another around the circumference of thearticulating bending neck.
 8. The articulating bending neck of claim 7,wherein the pivot lobe of the link and the shape of the adjoining linkare machined portions.
 9. The articulating bending neck of claim 1,further comprising: a sheath enclosing the plurality of pivotallyconnected links, wherein the sheath exhibits regions of differentdurometers along a length of the sheath.
 10. The articulating bendingneck of claim 9, wherein the regions of different durometers furthercomprises regions of different sheath thickness.
 11. The articulatingbending neck of claim 1, further comprising: a sheath enclosing theplurality of pivotally connected links, wherein the sheath exhibitspoints of attachment to the plurality of pivotally connected links alonga length of the sheath, wherein the points of attachment are moreclosely spaced along one section of the sheath relative to anothersection of the sheath.
 12. The articulating neck of claim 1, furthercomprising: a first control cable extending through the plurality ofpivotally connected links and anchored to a distal end of a firstsection of the plurality of pivotally connected links at a firstanchoring location, wherein, when the first control cable is pulled, thefirst section of the plurality of pivotally connected links isconfigured to articulate; and a second control cable extending throughthe plurality of pivotally connected links and anchored to the distalend of the first section of the plurality of pivotally connected linksat a second anchoring location, wherein the first anchoring location andthe second anchoring location are opposite to one another around acircumference of the articulating bending neck, wherein, when the firstcontrol cable and the second control cable are pulled, the first sectionof the plurality of pivotally connected links are in the lockedconfiguration to form a straight section.
 13. The articulating bendingneck of claim 12, further comprising: a third control cable extendingthrough the plurality of pivotally connected links and anchored to adistal end of a second section of the plurality of pivotally connectedlinks at a third anchoring location; and a fourth control cableextending through the plurality of pivotally connected links andanchored to the distal end of the second section of the plurality ofpivotally connected links at a fourth anchoring location, wherein thethird anchoring location and the fourth anchoring location are oppositeto one another around the circumference of the articulating bendingneck, wherein articulation of the first section of the plurality ofpivotally connected links and the second section of the plurality ofpivotally connected links are separately controlled.
 14. Thearticulating bending neck of claim 13, wherein the plurality ofpivotally connected links comprises a plurality of pivot lobes, whereinthe pivot lobe of the link is one of the plurality of pivot lobes of theplurality of pivotally connected links, wherein the first section of theplurality of pivotally connected links comprises a first subset of theplurality of pivot lobes and the second section of the plurality ofpivotally connected links comprises a second subset of the plurality ofpivot lobes, wherein the first subset of the plurality of pivot lobesand the second subset of the plurality of pivot lobes are aligned. 15.The articulating bending neck of claim 13, wherein the plurality ofpivotally connected links comprises a plurality of pivot lobes, whereinthe pivot lobe of the link is one of the plurality of pivot lobes of theplurality of pivotally connected links, wherein the first section of theplurality of pivotally connected links comprises a first subset of theplurality of pivot lobes and the second section of the plurality ofpivotally connected links comprises a second subset of the plurality ofpivot lobes, wherein the first subset of the plurality of pivot lobesand the second subset of the plurality of pivot lobes are offset by 90°around the circumference of the articulating bending neck.
 16. Thearticulating bending neck of claim 15, wherein the first anchoringlocation and the second anchoring location are offset by 90° around thecircumference of the articulating bending neck from the third anchoringlocation and the fourth anchoring location.
 17. The articulating bendingneck of claim 1, wherein the plurality of pivotally connected links aresized and shaped for insertion into an esophagus for trans-esophagealechocardiography.
 18. The articulating bending neck of claim 1, whereinthe link and the adjoining link comprise: a linear edge such that thegroove corresponds to a first articulation angle between the link andthe adjoining link; or a tapered edge such that the groove correspondsto a second articulation angle between the link and the adjoining link,wherein the second articulation angle is greater than the firstarticulation angle.
 19. The articulating bending neck of claim 1,wherein each of the inner tubular segment and the outer tubular segmentcomprise a metal.
 20. The articulating bending neck of claim 1, wherein,in the articulation configuration, the plurality of pivotally connectedlinks comprises different radii of curvature along the articulatingbending neck.